Relay



June 29, 1954 H. M. KNAPP 2,682,534

RELAY Filed May 24, 1952 2 Sheets-Sheet :l

M/l ENTOR By H. M. K/VA PP fcQ A T TOR/V5 V June 29 1954 H. M. KNAPP2,682,584

RELAY' Filed May 24, 1952 2 Sheets-Sheet 2 #vvavroe By H. M. KNAPPPatented June 29, 1954 UNITED STATES PATENT OFFICE RELAY Harry M. Knapp,Scotch Plains, N. J., assignor to Bell Telephone Laboratories,Incorporated, New York, N. Y., a corporation of New York Application May24, 1952, Serial No. 289,842

11 Claims. 1

This invention relates to switching devices, and more particularly toswitching devices for controlling a multiplicity of electrical circuits.

An object of this invention is to improve the efliciency, thecompactness and the economy of manufacture and maintenance of switchingdevices.

A further object of this invention is to improve the facility of aswitching device to transfer a first lead from a second to a third lead.

Another object of this invention is to increase the number ofcircuit-controlling elements of a switching device without increasingthe overall dimensions of the device.

A further object of this invention is to increasethe number ofcircuit-controlling operations which a switching device can perform.

A feature of this invention is an insulating element which not onlyserves accurately to fix the position of a plurality of contactelements, but also. serves to guide the movement of certain othercontact elements.

Another feature of this invention is the obtaining of transfer andcontinuity types of contact operation with but a single group of contactelements.

The principles of the invention have been exemplarily embodied in twotypes of electromagnetic switching devices or relays. The nature of theinvention may most clearly be understood from the following detaileddescription of those two embodiments of the invention, when read withreference to the accompanying drawings in which:

Fig. 1 is a plan view of one preferred embodiment of the inventionpartially cut away to show certain details of the construction moreclearly;

Fig. 2 is an elevational view of the relay shown in Fi 1;

Fig. 3 is a front-end view of the relay shown in Fig. 1;

Fig. 4 is an elevational view of a second pre ferred embodiment of theinvention, partially cut away to show certain details of theconstruction more clearly;

Fig. 5 is an elevational view of the relay shown in Fig. 4; and

Fig. 6 is a front-end view of the relay shown in Fig. 4 partially cutaway to show certain details more clearly.

- The relay disclosed in Figs. 1 to 3 of the drawings is also disclosed,and claimed, in the patent application of H. M. Knapp and C. F. Spahn,Jr., Serial No. 289,843, filed on even date herewith.

Referring first to the embodiment of the invention disclosed in Figs. 1to 3 of the drawings, the relay there disclosed comprises an E-shapedcore having three leg portions, I, 2 and 3 and a bridging portion 4which serves to interconnect the leg portions I, 2 and 3. Removablyplaced upon the center one of these leg portions 2 is an electromagneticcoil 5 having a front spoolhead 6. The terminals of the coil 5 areconnected to wires I which are mounted in the front spoolhead 6 andextend rearwardly of the relay through apertures in a molded element ofinsulating material 8 and appear at the rear of the relay as terminalsto which external circuits may be connected. A plurality of theseterminal wires 7 are provided so that coils having multiple windings maybe employed if desired.

The molded block 8 is substantially L-shaped in cross-section (the Lbeing inverted in the showing of Fig. 2) whereby a flat surface isprovided against which the upper side of the bridging member 4 or" thecore may rest. However, interposed between the upper surface of thebridging member A and this surface of the molded block 8 is a flatU-shaped spring member 9. By

' virtue of this construction, the bight of the U- shaped spring member9 is clamped between the lower surface of the oi fset portion of themolded block 8 and the upper surface of the bridging element of thecore.

The two leg portions of the spring member 9 extend forwardly in spacedproximity to the outer core legal and 3. The extreme forward ends of thelegs of the spring member 9 are provided with extending flange portionswhich may be wrapped or clinched around the tip ends of the legs IQ ofthe armature I I whereby the spring member 9 serves as a means forhinging the armature and for biasing that armature to its unoperatedposition. The clinched ends of the legs of the spring member 9 mayfurther be attached to the legs In of the armature II by welding, if

desired.

The armature I I is essentially U shaped in appearance, the bight of theU extending across the relay so as to be capable of bridging the threelegs I, 2 and 3 of the core. The leg portions ID of the armature I Iextend rearwardly of the relay and the tip ends of the legs Iii restagainst the legs of the spring member 9, which in turn rest against theouter core legs I and 3. Therefore, the armature H is pivotally mounted,the fulcrum being approximately at the extreme ends of the legs It ofthe armature II. The legs Iii of the armature i I may be of any suitablelength depending upon the operational requirements of 3 the relay. Thus,in the embodiment of the invention disclosed in Figs. 1, 2 and 3, thearmature legs have been made substantially as short as possible andstill provide a sufficient air-gap between the bight of the relay II andthe central core leg 2.

It will be seen that the electromagnetic circuits of the relay include afirst circuit comprising the center core leg 2, the core bridging member4, the outer core leg I, leg If! and the bight of the armature II, andan air-gap between the armature and the core. A similar path existsincluding core leg 3 and the other leg IQ of the armature II. Therefore,upon energization of the coil 5, a force will be exerted tending topivot the armature I I to a position in which it bridges the three corelegs I, 2 and 3, i. e., the forwardmost edge of the armature II willtend to move downwardly to engage the core, in the showing of Fig. 2.

Three layers of contact-holding elements are provided, and in thepreferred embodiments of the invention these contact-holding members arein the form of thin wires. The lowermost layer 50 and the uppermostlayer 52 of wires are movable, under the control of the armature,relative to the centermost layer of wires I. As may best be seen in Fig.2 of the drawings, the lowe1=- most set of these wires 5!! is molded orotherwise mounted in an insulating member I2 which engages the upperedge of the molded block 8. The centermost layer of wires 5I, which arepreferably of heavier construction than the lower and upper layers ofwires, are mounted in an intermediate block of insulating material I3which rests on block I2. To provide the requisite rigidity, it isadvantageous to provide a forward extension I4 for the block I3. Thecenter-most layer of wires 5| are preferably mounted in the block I3 andin its forward extension I4 during the operation in which blocks I3 andI4 are molded. Similarly, the upper layer of springs 52 are molded orotherwise afiixed in an upper molded block of insulating material I5which abuts the upper surface of block I3. Abutting the upper edge ofmolded block I5 is an essentially U-shaped balancing spring member It,the function of which will hereinafter be described.

In order accurately to position and retain the bridging portion 4 of thecore, the molded blocks 8, I2, I3 and I5 and the balancing spring It infixed position relative to one another, it is advantageous to providecorresponding projections and indentations in the several elements. Forexample, the balancing spring member I6 is apertured to engageprojections ll on the upper block I5. This group of elements is firmlyrendered integral by means of a clamp which has a top portion I8 and twoleg portions I9. The top portion I8 firmly engages the upper surface ofthe balancing spring member It and the leg portions I9 are .providedwith inwardly extending projections which engage the edges of theundersurface of the bridging portion 4 of the core. The upper surface I8of the clamp may be suitably deformed to provide a spring action.

The centermost layer of spring members 5| are affixed, preferably duringthe molding op eration, in a front molded block member 23, and passthrough that front molded block 23. Springs 5I are provided at theirforwardmost ends with contact elements 24. As may best be seen in Fig. 3of the drawings these contact members 24 are preferably square orrectangular blocks of metal with relatively thin layers of precious orlegs I, 2 and 5 accurately in a plane.

semi-precious contact metal at their upper and/ or lower edges.

In order that the centermost layer of fixed springs 5|, which areintegral with the front molded block 23, may be securely immobilized, acore plate 25 is provided. This core plate 25 performs a plurality offunctions. It is affixed to the front ends of the core legs I, 2 and 3by apertures in the plate 25 securely engaging these legs. This servesnot only to retain the core plate in position, but also greatly improvesthe economy of manufacture of the relay. The three apertures in the coreplate 25 which engage the core legs I, 2 and 3, may be accuratelylocated at relatively small cost. When the core plate is assembled tothe core, the core plate then serves accurately to position the threelegs I, 2 and 3 of the core with relation one to the other. Therefore,there is no necessity for machining the core legs to close tolerancesand no necessity for maintaining the upper surfaces of the core The coreplate serves to force those upper surfaces to be coplanar when the relayis assembled.

A portion 26 of the core plate 25 is bent forwardly so as to rest inproximity to a central forward extension 21 of the armature II. Thisprojection 26 serves as a back stop for the armature, i. e., it definesthe unoperated position of the armature. By virtue of this constructionthe back stop is centrally located on the armature and is positioned inline with the member 30 upon which the armatures force is exerted. Ithas been found that if the line of the armatures output force passesthrough the back stop member, armature rebound is substantiallyobviated.

The core plate 25 is also provided with two projecting arms comprisinghorizontal portions and 46 and vertically extending portions 41 and 48.The front molded block 23 rests against the uppermost edges of theupstanding arm portions 47 and 48, being firmly held against thoseportions primarily by the downward force exerted by the pretensionedsingle fixed springs 5| and also by the downward force exerted by thepretensioned twin springs 52. The horizontal portions 45 and II; areapertured so that a tool may be inserted to bend the horizontal portions45 or 46 up or down to adjust the position of the front molded block 23and thus to adjust the position of the fixed contact elements 24relative to the movable springs 50 and 52.

The upper and lower spring members 52 and 50, respectively, extendforwardly in approximate parallelism with one another and with the fixedsprings 5|, are provided with downwardly and upwardly extending offsetportions, respectively, at their forwardmost ends, and terminate inprecious or semiprecious metal contact elements. As may best be seen inFig. 3 of the drawings, two

. upper springs 52 and two lower springs 50 are provided for eachcontact element 24 of each fixed spring 5| so that upon any contactclosure two independent contacts engage a single fixed contact. Thisconstruction reduces the possibility of malfunctioning of the relay dueto dust or other impediments.

The upper springs 52 and the lower springs 50 are controlled by a movingcard 30 of insulating material. The member 30 is generally rectangularin external configuration and is suitably apertured to perform itsnecessary functions. The upper layer of springs 52 rest against theuppermost edge 35 of the card 30; the lowermost layer of springs 50 areengageable by an edge 36 of the moving card 30. The card is moveddownwardly upon the operation of the relay by virtue of an engagement ofa portion 31 of the card 30 with forwardly extending projections 38 ofthe armature H.

The uppermost layer of springs 52 are bent so as to be pretensioned in adownward direction. Theupper springs 52 therefore continuously exert aforce downwardly on the moving card 30 so that upon the downwardmovement of card 39 as a result of the operation of armature II, theupper layer of springs 52 are permitted to move downwardly to engage thefixed contact elements 24. Similarly, the lower layer of springs 50 arebent so as to be pretensioned upwardly into engagement with the fixedcontact elements 24. Therefore, upon a downward movement of the movingcard 30, the lower springs 50 are forcibly separated from the fixedcontact elements 24.

Upon the release of the relay and the return of the armature I l and themoving card 30 to their normal positions as shown, the upper layer ofsprings 52 will be forced back to their normal positions, as shown, andthe lower layer of springs 50 will be permitted to return to engagementwith the fixed contact elements 24.

The movement of the springs 52 and 50 both upon the operation and therelease of the relay is controlled not only by the moving card 3!) butalso by the front molded block 23. Thus, a plurality of tooth-likeprojections 43 are provided on the upper surface of the front moldedblock and the upper movable springs 52 are accurately laterallypositioned and guided thereby during their movement. Similarly, aplurality of projections 44 are provided on the lower surface of themolded block 23 to guide the lower springs 50 during their movement. Byvirtue of this arrangement, accurate lateral engagement of the movingsprings within the fixed contact elements is assured.

In certain uses of the relay the moving springs may be subjected tohigh-frequency vibratory chatter upon the operation or release of therelay. To avoid this condition, a shock absorbing material 54 may beaffixed to the portion 14 of the molded block 43 so as to press againstthe moving springs 50 and 52 to damp vibrations of those springs.

It will be noted that in the embodiment of the invention shown in Figs.1 to 3 which represent a relay of conventional size, there are twelvegroups of contact elements, each of which groups may comprise a fixedcontact element, an upper twin contact element and a lower twin contactelement. By virtue of the previously described operation, it will beperceived that the upper twin contact elements, mounted on the twinwires 52, are normally separated from the fixed contact elements 24 butthat upon operation of the relay these upper contact elements will bebrought into contact with the fixed contact elements 24, i. e., thefixed contact elements 24 and the upper contacting elements formso-called make combinations. If the edge of the moving card 30 bestraight and parallel with the fixed elements 24, all of the uppermoving springs 52 will simultaneously engage all of the fixed elements24. However, in some uses of the relay it may be found to be desirablefor selected ones of the uppermost springs 52 to engage the fixedcontact elements 24 at earlier or later times than others of those uppersprings 52 engage others of those fixed contact elements 24. If a slightdepression such as 4| (Fig. 3) is made in the upper edge 35 of card 30,the springs 52A which engage that slight depression will obviously makecontact with their associated fixed elements 24 at an earlier point inthe course of the downward movement of armature II than will others ofthe moving springs 52. These contacts may be labeled early makecontacts. Further, if an even deeper depression 42 be made in the edge35 of the moving card 30, the springs 52B engaging that deeperdepression will make contact not only prior to the time at which thenormal springs 52 make contact with their associated fixed elements 24,but als prior to the time at which the early make contacts 52A engagetheir fixed elements 24. This latter group of springs 523 may be labeledpreliminary make contacts.

It will also be perceived that by virtue of the above-describedoperation of the relay, the lower movable spring elements 50 arenormally in contact with their associated fixed contacts 24 and thatupon the operation of the relay and the consequent downward movement ofarmature I and moving card 30, this lower layer of springs 50 will breakcontact with their associated fixed elements 24. By providing similardiscontinuities (not shown) in the surface 35 of the moving card 33,early break contacts and preliminary break contacts may also beprovided. Conversely in both the case of make and break contacts, if thesurface 35 or 36 of the card 30 be provided with areas which projectupwardly or downwardly from the surfaces 35 or 35, respectively, latemake contacts and late break contacts may also be provided. However,three stages of make-contact and three stages of breakcontact operationare sufiicient for substantially all circuit requirements.

Assuming that each upper set of twin springs 52 may be of the normal,early or preliminary type, and that each lower set of twin contactsprings 53 may also be either normal, early or preliminary, it ispossible to provide for any one of fifteen different possible contactarrangements for each set of contacts. Thus, by omitting the set oflower springs 50 there may be provided a normal make contact set, anearly make contact set or a preliminary make contact set. Similarly, byomitting the upper pair of twin springs 52, a normal, an early, or apreliminary break contact set may be provided. By using both the upperset of twin springs 52 and the lower set of twin springs 5!! inconjunction with the fixed contact element 24, and by selecting whethereach of the upper sets and lower sets be normal, early, or preliminary,the following combinations of contact operation may, in an obviousmanner, be obtained: A breakmake combination in which both the upper andlower sets are either normal, ear1yorpreliminary; an early make-break,or a preliminary make-early break. or a preliminary makebreakcombination, all normally called continuities, in which the upper set oftwin wire contacts engages the fixed contact element 24 either somewhatbefore or substantially before the time that the lower set of contactsseparates from the fixed contact elements 24; and an early makebreak, ora preliminary break-early make, or a preliminary break-make combination,all normally called transfers, in which the lower set of twin wirecontacts 50 separates from the fixed contact 24 either somewhat beforeor substantially before the upper set of twin wire contacts 52 engagesthe fixed contact element 24. Similarly,

there may be early make-early break or preliminary make-preliminarybreak combinations.

These diverse combinations may be obtained primarily by the coding ofthe moving card 30, i. e., by the configuration of the surfaces 35 and36 of that card. If only make contact com-- binations or only breakcontact combinations are required, obviously either the surfaces 35 and35 of the card 30 must be so conformed that the springs never makecontact or never break contact, or else, more economically, one or moresets of springs 52 or 50 may be omitted or the contact elements may beremoved therefrom.

It will be seen that the possible combinations may be extendedconcatenatiously by strapping the terminals of adjacent groups ofcontacts in the well-known fashion, whereby a plurality of complexcombinations such as make-before break-before-make may be obtained ifcircuit conditions require.

Referring again to Figs. 1 and 2 of the draw-- ings, it will be notedthat the armature I I is subjected to a plurality of forces. The spring9 exerts a force tending to maintain the armature in its unoperatedposition, as shown in the drawings. The electromagnetic flux tends tomove the armature downwardly to bridge the core legs I, 2 and 3. Themoving card 30 exerts a downward force on the armature due to the factthat the moving springs 52 are pretensioned downwardly and consequentlyexert a force on moving card 30 in a downward direction. Balancingspring I6, which is connected to moving card 30, serves to exert anupward force on card 35 and, therefore, an upward force on armature I Iward force exerted by spring I6 is selected substantially tocounterbalance the force exerted by the moving springs 52 andconsequently the force exerted by balancing spring It must be varied inaccordance with the degree of pretensioning of the springs 52 and thenumber of springs 52 which are provided.

In special uses of the relay, it may be desirable to have an additionalforce exerted on the armature tending to restore that armature tonormal. If such force be required however, it is normallydisadvantageous to have that force continually exerted inasmuch as suchforce would. also oppose the movement of the armature during itsoperation. Buffer spring 55 is operative to exert a force to assistrestoration of the armature to normal but does not impede the downwardmovement of the armature until after all contact operations have beencompleted. Buffer spring 55 is essentially U-shaped, having a crosspiece56 and two legs 51. A projection 58 (Fig. 2) extends upwardly from thecross-piece 56 and engages the lower edge of the middle core leg 2. Theextreme ends of the legs 51 of spring 55 press against the lowersurfaces of the outer core legs I and 3, and at a point on the bufferspring 55 intermediate the projection 53 and the extreme ends of thespring legs 51, the spring legs 51 engage projections on the spoolhead6. The projections on the spoolhead B are so located that the legs 51 ofthe buffer spring 55 are slightly deformed when the buffer spring is inposition on the relay, and the resulting tension of the spring legs 51serves to retain the buffer spring 55 in position. An additionalupstanding per- The uption 59 is provided on cross-piece 56. Thisportion 59 is so located that the lower edge of the moving card 30 willcontact it when the relay is operated. Consequently, just prior to thecompletion of the operation of armature I I, the moving card 30 willengage the buffer spring and bend it downwardly. When the coil 5 isdeenergized the buffer spring 55 will be effective to exert anadditional upward force to assist the return of the armature II tonormal.

While the use of twin contact elements mating with. single contactelements substantially obviates the possibility of malfunctioning of therelay in the presence of dust or other impurities, a contact cover maybe provided further to insure proper operation and also to preventdamage through mishandling. This cover is arranged to engage the frontmolded block 23 on all four sides to create a substantially dust-tightenclosure for the contacts. It will be noted that since the contactcover 50 engages the upper extremes of the projections 43 and the lowerextremes of the projec tions it on the front molded block 23, thecontact cover also serves to insure that the springs 52 and 56 will betrapped in their proper positions and yet that, upon removal of thecontacts, the springs 52 and 50 may be readily displaced so that themoving card 35 may be removed and a card of different surfaceconfiguration inserted for coding purposes.

The embodiment of the invention disclosed in Figs. 4 to 6 is quitesimilar for the most part to the embodiment shown in Figs. 1 to 3.Consequently, except as to the differences in construction, the detailsof the embodiment shown in Figs. 4 and 6 will be described in a somewhatless detailed manner.

A plurality of molded insulating blocks I03 to IM are firmlyinterassociated by a clamping member I53. A core member having threelegs I33, Ill} and III is clamped between insulating blocks its and E05,and an energizing coil H2 is mounted upon the center core leg H0. Theterminals of the windings of coil II2 are connected to wires H3 whichextend through apertures in insulating block I03. A lowermost set oftwin wire movable contact springs H4 is molded in and extends throughinsulating block Hi5 and an upper set of twin wire contact springs H5 ismolded in and extends through insulating block I01. A multifingeredbalancing spring I20 is clamped between the upper molded insulatingblock I0? and the upper portion of clamp I08. The several elementscontained by clamp I08, including the balancing spring I20, the core andthe molded insulating blocks I03 to I01, may have matching projectionsand indentations to assure permanency of registration.

A U-shaped armature I2! is mounted so that the rearwardmost tips of thelegs of armature I2I engage the outer legs I09 and III about the core. Aspring member I22 engages each of the legs of armature I2I and isclamped between the core and the fixed insulating block I05 in such afashion that it hinges the armature I2I to the core.

The unoperated position of armature I2I is established by a back-stopelement I23 on the core plate I24, a projection I25 at the front of thearmature passing through an aperture in the core plate I24 so as to beengageable with the back-stop projection I23.

The fixed contact elements I30 comprise blocks of metal faced at theirupper and lower surfaces with precious or semi-precious metal contactingsurfaces. These fixed contact elements I 33 are welded or otherwiseafiixed to vertically extending wires I3I. As may best be seen in Fig.5, these wires I3I are molded or otherwise afiixed in a frame-like frontmolded member I32, extend downwardly, are molded or otherwise affixed ina front retaining element I33 of insulating material and then extendrearwardly and are molded or otherwise aflixed in insulating block I03.The front retaining element I33 is provided with projections I34-whichengage extensions I 35 oncore plate I24. Since apertures in core plateI24 firmly engage and position the front ends of the core legs I09 130'III, the core plate is integral with the core. Therefore, since thefront retaining element I33 is integral with the core plate I24, elementI33 is also integral with the core. In this manner the wire springs I3Iare firmly fixed in position.

As maybest be seen in Fig. 6 of the drawings, the front molded memberI32 is frame-like in appearance being provided with two horizontalcrosspieces I40 and MI joined by two vertical side pieces I42. Thefixed, single wire springs I3I are molded in both the lower .and uppercrosspieces I40 and I II and extend parallel to the side members I42.The moving twin wire springs I I4 and H extend through individualapertures defined by the lower horizontal member I or the upperhorizontal member I40 respectively, of the front molded member I32, bythe fixed contact elements I and by the vertical spring wires I3I. It isobviously imperative that the twin contact springs H4 and II5 not engagethe wires I3I since such engagement would constitute an erroneouscircuit closure. Therefore, horizontal portions I45! and MI are providedwith projecting cylinders of insulating material I45 which surround thefixed wires I3I over that portion of their lengths between the fixedcontact elements I30 and the upper or lower horizontal members I or I4I.Therefore, the vertical cylindrical projections I of the front moldedmember I32 serve to guide the twin wire springs H4 and II 5 during theirmovement. 7

The movement of the twin wire moving springs II 4 and H5 is furthercontrolled by a moving card I 47 which engages projections I48 (Fig. 6)of armature I2I so as to be controlled by the movement of the armature.the extreme upper edge of the moving card I41 engage the outermostfingers I5I and I52 of the balancing spring 0 I20 whereby the card I4!is maintained in proper position and is biased upwardly to assist thearmature I2I to restore to its normal position. The centermost fingersI53 and I54 of the balancing spring I20 are pretensioned oppositely tothe outermost fingers I5I and I52, i. e., are pretensioned downwardly.The innermost fingers I53 and I54 engage projections I55 on the upperedge of the front molded member I32 so as to assist in fixing theposition of member I32.

It will be seen from the above description that upon the energization ofcoil II2 armature I2I will be attracted downwardly into engagement withthe core whereby moving card I41 will also be moved downwardly. Sincethe upper set of springs I I5 is pretensioned so as to tend to movedownwardly, and since the lower set of twin springs H4 is pretensionedso as to tend to move upwardly into engagement with the fixed contactelements I30, upon the downward movement of card I41 the upper twin wiresprings I I5 will be permitted to move into contact with the fixedelements I30 and the twin wire springs I I4 will be forced to disengagecontact with the fixed contact elements I30. Conversely, upon the de-Projections I50 at I 10 energization of coil H2 and the resultantrelease of armature I2I, moving card I41 will return upwardly wherebythe lower twin wire springs H4 will be permitted to reengage the fixedcontact elements I 30 and the upper twin wire springs H5 will be forcedto disengage the fixed contact elements I30.

Since the movement of the upper twin wire springs H5 is controlled bythe surface I60 (Fig. 6) of the moving card I i? and since the movementof the lower twin wire springs H4 is controlled by the configuration ofsurface I 6| of moving card Ml, coding of the relay may be accomplishedin a manner similar to that previously described with reference to theembodiment depicted in Figs. 1 to 3 of the drawings, that is, thesurface IE5 or I5I contacting any given pair of twin wire springs may beelevated or depressed to control the time at which that pair of springswill make or break. contact with the fixed contact element I 30 relativeto the time at which the other twin wire contact springs will make orbreak contact. Consequently, any one group of springs comprising onepair of upper springs H5, one pair of lower springs H4 and one contactelement I30 may be arranged to provide any of the aforesaid fifteen ormore types of contact combinations including normal, early andpreliminary makes and breaks, and the plural variations of transfers andcontinuity con- It is to be understood that the above-describedarrangements are but illustrative of the principles of the invention.Numerous other arrangements may be devised by those skilled in the artwithout departing from the spirit and scope of the invention.

What is claimed is:

1. In a switching device, a molded block of insulating material, meansfor fixing said block, a plurality of fixed wire springs molded in saidblock, contact elements mounted on said fixed wire springs, each of saidelements having two faces, a first and a second plurality of movablewire springs, contact surfaces on said first plurali'ty of movable wiresprings engageable with one face of said contact elements, contactsurfaces on said second plurality of movable wire springs engageablewith the other face of said contact elements, and means for controllingthe movement of said movable contact springs.

2. In a switching device, a molded block of insulating material, meansfor fixing said block,

a plurality of fixed wire springs molded in said block, contact elementsmounted on said fixed wire springs, each of said elements having twofaces, a first and a second plurality of movable wire springs, aplurality of projections on said block engagingsaid movable wiresprings, contact surfaces on said first plurality of movable wiresprings engageable with one face of said contact elements, contactsurfaces on said second plurality of movable wire springs engageablewith the other face of said contact elements, and means for controllingthe movement of said movable contact springs.

3. In a switching device, a molded block of insulating material, meansfor fixing said block, a plurality of fixed wire springs molded in saidblock, contact elements mounted on said fixed wire, springs, each ofsaid elements having two faces, a first and a second plurality ofmovable wire springs, a plurality of projections on said block extendingperpendicularly to said movable wire springs, each of said movable wiresprings engaging adjacent ones of said projections, contact surfaces onsaid first plurality of movable wire springs engageable with one face ofsaid contact elements, contact surfaces on said second plurality ofmovable wire springs engageable with the other face of said contactelements, and means for controlling the movement of said movable contactsprings.

4. In a switching device, a molded block of insulating material, meansfor fixing said block, a plurality of fixed wire springs molded in saidblock, contact elements mounted on said fixed wire springs, each of saidelements having two faces, a first and a second plurality of movablewire springs, contact surfaces on said first plurality of movable wiresprings engageable with one face of said contact elements, contactsurfaces on said second plurality of movable wire springs engageablewith the other face of said contact elements, and an operating card forcontrolling the movement of said movable wire springs, said firstplurality of movable wire springs being pretensioned against saidoperating card, and said second plurality of movable wire springs beingpretensioned against said contact elements.

5. In a switching device, a molded block of insulating material, meansfor fixing said block, a plurality of fixed wire springs molded in saidblock, contact elements mounted on said fixed wire springs, each of saidelements having two faces, a first and a second plurality of movablewire springs, contact surfaces on said first plurality of movable wiresprings engageable with one face of said contact elements, contactsurfaces on said second plurality of movable wire springs engageablewith the other face of said contact elements, and a vertically movableoperating card for controlling the movement of said movable wiresprings, said card having an upper surface and a lower surface, saidfirst plurality of movable wire springs being pretensioned downwardlyagainst the upper surface of said card, and said. second plurality ofmovable wire springs being pretensioned upwardly against said contactelements and being engageable by the lower surface of said card.

6. In a switching device, a molded block of insulating material, meansfor fixing said block,

a plurality of fixed single wire springs molded in said block, contactelements mounted on said fixed wire springs, each of said elementshaving two faces, a first and a second plurality of movable twin wiresprings, a plurality of projections on said block extendingperpendicularly to said movable wire springs, each of said movable wirespringsengaging adjacent ones of said projections, contact surfaces onsaid first plurality of movable wire springs engageable with one face ofsaid contact elements, contact surfaces on said second plurality ofmovable wire springs engageable with the other face of said contactelements, and a vertically movable operating card for controlling themovement of said movable wire springs, said card having an upper surfaceand a lower surface, said first plurality of movable wire springs beingpretensioned downwardly against the upper surface of said card, and saidsecond plurality of movable wire springs being 1 2 pretensioned upwardlyagainst said contact elements and being engageable by the lower surfaceof said card.

7. In a switch, a plurality of contact springs, means for controllingthe movement of said contact springs, a plurality of contact membersextending perpendicularly to said contact springs and engageabletherewith, and an element of insulation material molded on said contactmembers, said element having a first portion lying in a plane above saidplurality of contact, springs, a second portion lying in a plane belowsaid plurality of contact springs, a third portion lying in a plane toone side of said plurality of contact springs, and a fourth portionlying in a plane to the other side of said plurality of contact springs.

8. In a switch, a plurality of contact springs, means for controllingthe movement of said contact springs, a plurality of contact membersextending perpendicularly to said contact springs and engageabletherewith, and an apertured frame of insulating material molded on saidcontact members, said contact springs extending through the aperture insaid frame.

9. In a switch, a plurality of contact springs, means for controllingthe movement of said contact springs, a plurality of contact membersextendin perpendicularly to said contact springs, 21. contact element oneach of said contact members extending perpendicularly to both saidcontact springs and saidcontact members, and an apertured frame ofinsulating material molded on said contact members, said springsextending through the aperture in said frame and engage able withindividual ones of said contact elements.

10. In a switch, a plurality of groups of contact springs, means forcontrolling the movement of said contact springs, a plurality of contactmembers extending perpendicularly to said contact springs and engageabletherewith, and an apertured frame of insulating material molded on saidcontact members, individual ones of said groups of contact springsextending through an aperture defined by said frame and by adjacent onesof said contact members.

11. In a switch, a plurality of groups of contact springs, means forcontrolling the movement of said contact springs, a plurality of contactmembers extending perpendicularly to said contact springs, a contactelement on each of said contact members extending perpendicularly toboth said contact springs and said contact members, and an aperturedframe of insulating material molded on said contact members, individualones of said contact springs extending through individual aperturesdefined by said frame, by adjacent ones of said contact members, and byindividual ones of said contact elements.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 1,647,792 Gent Nov. 1, 1927 2,282,687 Vigren et a1. May 12,1942 2,312,493 Sengebusch Mar. 2, 1943 2,452,568 Harrison Nov. 2, 19482,566,840 Krumreich Sept. 4, 1951

